1. Field of the Invention
The present invention relates to a probe cover for an ear thermometer, particularly to a design, which can prevent the variation of the infrared transmittance of the probe cover film and avoid the error of body temperature measurement.
2. Description of the Related Art
Nowadays, it is very popular to measure the body temperature with an ear thermometer. However, the ear thermometer has to reach into the ear canal. For sake of hygiene, the probe of an ear thermometer is sleeved with a probe cover lest dirt and germs pollute the probe.
FIG. 1A shows a probe cover of a tympanic thermometer and tympanic thermometer assembly disclosed in U.S. Pat. No. 6,647,284 B1. The conventional probe cover comprises a base 16 and a frustum-shaped sheath 12. The frustum-shaped sheath 12 has a cover window 121 able to contact the probe window 14 of an ear thermometer and a cover sidewall 122 able to contact the probe casing. The cover window 121 is thicker than the cover sidewall 122; moreover, the thickness of the cover sidewall 122 is gradually getting thinner from the base 16 to the cover window 121. Thus, the thickness of the probe cover is b<c<d<a.
Refer to FIG. 1B. However, when the probe is sleeved with the frustum-shaped sheath 12, the cover window 121 is usually hard to exactly coincide with the probe window 14, i.e. the film covering the probe window 14 is not completely the film of the cover window 121 but partially the film of the cover sidewall 122. In such a case, the infrared light will pass a film with a non-uniform thickness so the result of temperature measurement will be inaccurate. Furthermore, the other consideration causes a heavy burden which is that the cover window 121 needs to be situated exactly in the center of the frustum-shaped sheath 12 during manufacturing. Otherwise, the conventional probe cover will be unsuitable to coincide with the the probe.
Accordingly, the present invention proposes a probe cover for an ear thermometer to overcome the abovementioned problem.